If we assume that what characters see and hear are facts, they may not always be but we’re keeping it simple, then how they interpret the ‘facts’ is what they think they know. When we’re writing a first-person/subjective narrative then we have to remember that the ‘truth’ and what the character thinks is the truth might not be the same. Characters, like people, can be exposed to the same facts and interpret them differently based on their backstory and world view.
An example of this would be characters interpreting the actions of others. A suspicious character may look at a good act and try to work out the other character’s angle, what advantage there is for performing a good act, while a more trusting character may take it as a good act for good reasons. One or other may be true, or it may be more complicated but that character will perceive it as what they know when really it’s what they think.
Subjective narrators have an opinion on everything, even if that opinion is not conspicuously expressed it will colour what they say. This could be a simple as a jewel thief noticing all those expensive diamonds in the jewellers but paying no attention to the wallpaper or more complex where each characters actions are noted and veiled in suspicion. As we discussed in the articles on setting we can use what a character describes to tell us about the character and it’s something important to bear in mind when we’re writing a first-person narration. To go back to the idea of the jewel thief it would be odd if they walked into a scene and described the wallpaper and paid no attention to the things they could steal. This doesn’t mean they have to steal them, simply that they would notice them. In this case the room might have some fantastic interior design but if our narrator isn’t interested they will either brush over it or not describe it at all.
The same can apply to other characters. They may mention a character but if they hold no interest not talk about them much, this can be one way to fool the reader about the importance of a character. In this case the narrator thinks the other character isn’t important but they are. Alternatively the narrator’s mind set might lead them to describe another character as if they are an antagonist when they’re on the same side and someone else is the antagonist. We all have people in real life that we don’t get on with, this doesn’t mean they’re bad people we just don’t get on, so if we were narrating a story in which they were mentioned then they would become antagonists.
Similarly when a character is acquiring information from other characters there will be those the character thinks they know are trustworthy and those they think they know aren’t. This is another way to mislead the reader, and the narrator, when the ‘trustworthy’ character turns out to be untrustworthy, or even the antagonist themselves. Or the narrator might miss out on important information based on their opinion of the character they’re talking to. If a character they consider ‘untrustworthy’ claims to have information they’re more likely to discount them or ignore them, which may prove a fatal mistake.
It is important to remember that a first-person/subjective narrator’s voice is never neutral, even if they claim to be. Everything they reveal is coloured by their view of the world and their motivations.